Nuclear Techniques ›› 2017, Vol. 40 ›› Issue (11): 110501-110501.doi: 10.11889/j.0253-3219.2017.hjs.40.110501


Physical design of fast fission chamber for neutron spectrum and flux measurement at the CSNS backstreaming white neutron source

LUAN Guangyuan1, WANG Qi1, BAO Jie1, RUAN Xichao1, REN Jie1, JING Hantao2,3, ZHANG Kai1, HUANG Hanxiong1   

  1. 1 Key Laboratory of Nuclear Data, China Institute of Atomic Energy, Beijing 102413, China;
    2 Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China;
    3 Dongguan Neutron Science Center, Dongguan 523803, China
  • Received:2017-02-07 Revised:2017-03-19 Online:2017-11-10 Published:2017-11-08
  • Supported by:
    Supported by National Key Research Program of China (No.2016YFA0401601), the Special Foundation for Nuclear Data (No.3210401)

Abstract: Background: The backstreaming white neutron source (Back-n) of China spallation neutron source (CSNS) will provide pulsed white neutron beam with a high fluence rate for nuclear data measurement. The accurate measurement of the neutron spectrum and fluence rate after the Back-n's completion will be the basis of the following physical experiments. Purpose: This study aims to design a fast fission chamber for the CSNS Back-n flux measuring and monitoring system. Methods: The detector performance including time resolution, particle distinction and detection efficiency was studied by experiments. Based on the study, the parameters of the fission chamber were determined, and its detection efficiency calculated by the 235U sample quantity was compared with that measured by concomitant particle method. Results: Considering the particle distinction, the distance between the anode and the target of the fission chamber was determined as 10 mm, the time resolution of the fission chamber was measured to be about 15 ns. The deviation of calculated detection efficiency from the measurement was in the range of 5%. Conclusion: According to the detection efficiency and the demand of the neutron flux monitoring, the quantity of the uranium for the fast fission chamber can be determined. With appropriate parameters, the fast fission chamber can be used in CSNS Back-n flux measuring and monitoring.

Key words: Fission chamber, CSNS, White neutron source, Neutron time-of-flight facility

CLC Number: 

  • TL816+.3